The present invention relates to improvements in an aluminum alloy can end of the aluminum alloy can which can end is formed with a score for severing the area defined thereby from the can end so as to provide an opening for taking out the content of the can, and, more particularly, to a can end of the type described above which has a high pressure resisting strength against the internal pressure caused by pressurized liquid or pressure generating liquid contained in the can such as carbonated beverage including beer, for example, while it provides a great aperture rate of the can end as defined by the ratio of area of the opening with repect to the total area of the can end such as ranging equal to or greater than 60%.
In an aluminum alloy can for containing beer therein which is being commonly sold at present, the body of the can having a bottom integrally formed therewith has the shape similar to that of a conventional aluminum alloy can for containing juice therein and the body is made of an aluminum alloy sheet of Japanese Industrial Standars (referred to as JIS hereinafter) A-3004 P.H-19 having the thickness of about 0.35 mm and formed by the deep drawing and ironing process, while the can end of the can which is sealingly curled with its peripheral portion toegeher with the peripheral upper open end of the body is made of an aluminum alloy sheet of JIS A-5052 P.H-38 having the thickness of about 0.30 mm (in case of a can having the internal volume of 350 ml), for example. The configuration of the periphery of the can end is in the frustoconical shape and a teardrop-shaped severing score is formed in the can end by the pressing process, and a manipulating tab having a gripping hole formed therein is secured to the severable area defined by the score of a relatively small aperture by a rivet located at a position near the tip of the teardrop-shape of the severable area, whereby the severable area can be removed from the can end by pulling the tab apart from the can end so that the rivet first breaks off the tip portion of the teardrop-shape of the severable area to which the rivet is secured along the score thereby providing an opening for taking out the content of the can.
In general, beer is said to taste most delicious when one gulps down the beer or takes a long noisy drink of the beer after it is cooled to a temperature of about 5.degree.-10.degree. C.
The discharge rate of beer out of a prior art can through the opening formed in the can end is low, so that good taste of beer can not be obtained by using the prior art can presently produced and sold. This tendency is enhanced as the volume of the can decreases, even though the relationship between the aperture rate and the volume of the can containing beer therein is taken into consideration.
In order to solve the above problem, efforts have been made to increase the aperture rate of a can. However, since beer contains carbonic acid gas so that the internal pressure of a can containing therein beer will sometimes rise to about 5 kgf/cm.sup.2 or more in the summer season, for example, when the can directly receives the sunlight, construction of a can end has not ever been developed which can satisfy the requirements such as to sufficiently resist against such a high internal pressure and yet to be easily opened while it has a large aperture rate for achieving good taste of beer, and can be produced at a lower cost.